Apparatus for preventing accumulation of oil in cooling compartment of ice cream freezers



J. T. SMITH July 31, 1934.

APPARATUS FOR PREVENTING ACCUMULATION OF OIL IN COOLING COMPARTMENT OF ICE CREAM FREEZERS Filed Feb. 29, 1932 Patented July 31, 1934 UNITED STATES APPARATUS FOR PREVENTING ACCUMU- LATION OF OIL IN COOLING COIVIPART- MENT OF ICE CREAM FREEZERS James T. Smith, Chicago, Ill., assignor to Mills Novelty Company, Chicago, Ill., a corporation of Illinois Application February 29, 1932, Serial No. 595,844

6 Claims.

This invention relates to ice cream freezers of the type in which cooling of the cream mix is effected by the direct expansion of a refrigerating medium in the cooling compartment of the 5 freezer.

The object of the invention is to provide in a refrigerating system for a freezer of the type referred to means whereby oil which enters the system from the compressor may be prevented from accumulating in the cooling chamber of the freezer.

The invention will be fully understood from the following, detailed description, taken in connection with the accompanying figure of drawings, wherein I have shown a diagram of a freezer refrigerating system embodying the principles of the invention.

Briefly, the invention consists in the provision of means whereby liquid refrigerant remaining in the cooling compartment of the freezer at the end of the-freezing operation may be removed therefrom and conducted to the suction compartment of the compressor. The oil which invariably becomes commingled with the refrigerant as it passes through the compressor is thus returned to the latter after .each freezing operation, and is thereby prevented from accumulating in the freezerjacket and eventually causing reduced efliciency.

In the drawing the numeral 5 designates a freezer of the horizontal type which is supported at its opposite ends by standards 6 and '7, the latter, in turn, being supported on the top wall of a mix cooling cabinet 8. The drive means for the agitating mechanism of thefreezer is contained within a housing 9 adjoining the closed end of the freezer. Cream mix is introduced into the freezer cylinder (not shown) through a funnel member 10 carried by the door at the front end of the freezer. The semi-frozen mix is drawn off through an outlet 11 which is also carried by the door at the front end of the freezer A jacket 12, arranged in spaced relation to the freezer cylinder. forms with the lat ter a compartment for receiving a-refrigerating medium such as methyl chloride or the like.

. The mix cooling cabinet 8, upon which the freezer is supported, is preferably partitioned off to provide in the lower portion thereof a compartment in which cans containing the cream mix may be stored preparatory to freezing. The mix storage compartment is cooled by an element 13 which is connected in the refrigerating system in a manner presently to be explained.

The refrigerant is circulated through the freezer, and element 13, by a compressor-condenser unit which may be of any Preferred form- In the embodiment shown this unit comprises: a compressor 14, supported upon a base 15; a condenser 16, positioned on base 15 adjacent the condenser, and connected to the latter by means of a conduit 17; and an electric motor 18, supported on base 15 adjacent the compressor and having drive connection with the latter through a belt 19.

The circuit by which liquid refrigerant is supplied from condenser 16 to the cooling chamber of the freezer is traced from a conduit 21, which leads from the lower portion of the condenser to a conduit 22, the latter connecting through an inlet shut-off valve 23 to a liquid storage tank 24. From tank 24 the supply of liquid refrigerant is conducted through an outlet shut-off valve 25 and a conduit 26 to a thermostatic expansion valve 27. From valve 2'7 liquid is supplied through pipes 28 and 29 to an inlet opening located in the lower portion of the cooling chamber of the freezer.

The freezer is operated on the hooded system, valve 27 being arranged to maintain the liquid at a proper level in the cooling compartment of the freezer. As the liquid passes through pipe 29 into the cooling compartment of the freezer, it starts to evaporate under the heating action of the warm mix in the freezer cylinder. The hubbles of vapor pass upwardly through the body of liquid in the cooling chamber and are removed from the upper portion of said chamber through a vapor take-off 31 which connects through a two-way valve 32 to a suction line 33 which returns the vapor to the suction compartment of compressor 14. The power element 34 of expansion valve 27 is positioned adjacent the vapor take-off line 31, thereby automatically adjusting valve 27 in accordance with the temperature of line 31 to maintain a proper. liquid. level in the cooling compartment of the freezer.

One of the difficulties encountered in the operation of a freezer on the flooded system is the tendency of oil .to accumulate in the chamber surrounding the freezer cylinder. Whatever type of compressor may be used, there is always more or less tendency for oil to become entrained with the refrigerant. This oil is carried along with liquid refrigerant into the cooling chamber of the freezer and, since it does not evaporate with the refrigerant, tends to accumulate around the cylinder and greatly retards the freezing process.

In accordance with my invention, means is provided whereby after each freezing operation the liquid remaining in the cooling chamber of the freezer is conducted to the compressor, thereby removing the oil entrained therewith from the cooling chamber. This removal of liquid refrigerant from the freezer is accomplished by supplying liquid refrigerant to cooling element 13 through a conduit 35 which connects through a T-connector 36 with the pipes 28 and 29 which supply liquid refrigerant from valve 27 to the freezer. The vapor return for element 13 comprises a conduit 3'7 which connects through two-way valve 32 with suction line 33. A thermostatic expansion valve 38 connects liquid supply line 35 with the coil of element 13. The power element 39 of valve 38 is positioned adjacent vapor return line 3'7 to automatically control the supply of refrigerant to the coil of element 13.

The two-way valve 32 is arranged so that in the on position it connects vapor return line 31 to suction line 33 and in this position maintains vapor return line 37 closed. In the off position return line 3'7 is connected with suction line 33 and line 31 is closed. This valve is operated through a hand piece 41 which is positioned on the front panel of cabinet 8. The valve is held in the on position during the freezing operation to allow circulation of refrigerant through the freezer, and as the freezing operation is completed, it is thrown to the off position, thereby stopping flow of refrigerant to the freezer and automatically establishing flow of refrigerant to element 13. A valve mechanism suitable for this purpose is shown in my co-pending application, Serial No. 595,685, filed February 29, 1932. J

The operation of the oil return system is as follows:

Starting with valve 41 in the "on position, liquid refrigerant surrounds the freezer cylinder, being supplied thereto through valve 27 in amounts sufficient to cool the cream mix. The vaporized refrigerant is returned through line 31, valve 32, and line 33 to the compressor. After the I mix has been frozen to the desired consistency the fiow of vapor from the freezer is stoppedto prevent further refrigeration in the freezer by turning valve 32 to the off position, thereby automatically closing vapor return line 31 and opening vapor return line 37. The opening of ,line 3'7 starts circulation of refrigerant through cooling element 13, the supply of liquid refrigerant for said element being taken from valve 27 through pipe 28 and conduit 35 to valve 38, the latter connecting with the coil of element 13. vaporized refrigerant is returned from the coil of element 13 through line 3'7, valve 32, and line 33 to the compressor. In addition to this direct supply of liquid refrigerant from valve 27 to element 13, there is returned through said element back to the suction compartment of the compressor the refrigerant which remains in the cooling chamber of the freezer upon the turning of valve 32 to the off" position. This refrigerant is removed from the lower portion of the cooling chamber of the freezer through pipe 29, which connects through T-connector 36 with line 35, the latter, as previously explained, serving toconduct liquid refrigerant to element 13. This body of liquid refrigerant which remains in the cooling chamber of the freezer is forced back through line 35 by the back pressure which builds up in the cooling chamber upon the throwing of valve 32 to the "off position. In the embodiment shown, element 13 is positioned below the freezer, and therefore the force of gravity also aids in the removal of the refrigerant remaining in the cooling chamber. However,the back pressure in m chamber would be sufficient to force the liquid therefrom even though element 13 were positioned above the freezer. The oil which is entrained with the liquid in the cooling chamber of the freezer is carried back with the liquid through lines 29 and 35 to valve 38. Although transformation of the refrigerant from a high to a low pressure liquid is effected in valve 38, the rate of flow of the refrigerant from that point through the coil of element 13 and lines 37 and 33 to the compressor is sufficiently high to carry the oil back along this path to the suction compartment of the compressor. The arrangement thus permits the return of whatever oil may have accumulated in the cooling chamber of the freezer during the freezing operation to the compressor at the end of each freezing operation, thereby preventing accumulation of oil around the freezer cylinder.

In the refrigerating system shown in thedrawing there is also provided a hardening cabinet 42 which is used to cool the frozen cream from a temperature of about 25 F. to a temperature of between 5 F. and 10 F. This cabinet is provided with a series of cooling slabs 43 which are filled with an anti-freeze solution and which are cooled by the passage of refrigerant through coils contained therein. The supply of refrigerant to hardening cabinet 42 is from line 21 through a T- connector 44 to a conduit 45 which connects with a thermostatic expansion valve 46, the latter connecting through a pipe 47 with the coil in the first of the series of cooling slabs 43. Vapor return from cabinet 42 is through a conduit 48 which connects at 49 with the vapor return line 37 for cooling element 13. The hardening cabinet is merely an-auxiliary feature and does not form a part of the oil return circuit for the freezer.

While in the embodiment shown the freezer and cooling element 13 are arranged for alternate operation, this being accomplished through the use of two-way valve 32, the invention is not to be understood as confined to this particular type of arrangement. For example, cooling element 13 can be arranged to operate continuously, this being effected by the provision of separate vapor return lines for said element and the freezer. In this event a valve would be positioned in the vapor return for the freezer to interrupt the fiow of refrigerant to the freezer at the end of a freezing operation.

The foregoing detailed. description has been given for clearness of understanding only, and nounnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prising, in combination, a freezer provided with a compartment for receiving a refrigerating medium, a compressor, a condenser associated with said compressor, connections for conducting liquid refrigerant from said condenser to the freezer and for returning vaporized refrigerant from the freezer to the compressor, means for interrupting the flow of refrigerant vapor from the freezer, and means, including a heat exchange element and an expansion valve associated therewith, providing a path whereby liquid refrigerant, and any oil entrained therewith, remaining in the freezer upon stoppage of flow of refrigerant vapor therefrom, may be removed from the freezer and conducted through said exchange element and the expansion valve to the suction compartment of the compressor, thereby preventing accumulation of oil in the refrigerant compartment of the freezer.

2. Apparatus of the character described, comprising, in combination, a freezer provided with a compartment for receiving a refrigerating medium, a compressor, a condenser associated with said compressor, a refrigerating unit and a cooling element therefor, an expansion valve associated with said cooling element, connections for supplying liquid refrigerant from said condenser to the freezer and the refrigerating unit, additional connections for returning vaporized refrigerant from said freezer and the refrigerating unit to the compressor, and valve means for opening and closing the vapor return leading from the freezer to the compressor, the liquid supply con-' nections for said freezer and the refrigerating V prising, in combination, a freezer provided with a compartment for receiving a refrigerating medium, a compressor, a condenser associated with said compressor, a refrigerating unit, and a cooling element therefor, an expansion valve associated with said cooling element, a vapor return line for conducting vaporized refrigerant from the freezer to the condenser, a second vapor return line for conducting vaporized refrigerant from the refrigerating unit to the return line for the freezer, valve means interposed in the vapor return for the freezer at its point of connection with the return for said refrigerating unit for simultaneously opening one of said returns and closing the other, and connections for supplying liquid refrigerant from the condenser to saidfreezer and said refrigerating unit, said supply connections being interconnected to provide a path whereby upon closing of the vapor return for the freezer and opening of the vapor return for said refrigerating unit, liquid refrigerant, and any oil entrained therewith, remaining in the freezer may be removed from the latter and conducted through said expansion valve and cooling element to the suction compartment of the compressor, thereby preventing accumulation of oil in the refrigerant compartment of the freezer.

4. Apparatus of the character described comprising, in combination, a freezer provided with a compartment for receiving a refrigerating medium, a compressor, a condenser associated with said compressor, a refrigerating unit, including a cooling element provided with an expansion valve, connections for returning vaporized refrigerant from said cooling element and the refrigerant compartment of the freezer. to the compressor, the connection for the freezer having valve means therein for opening and closing the vapor return leading from the freezer to the compressor, and means for supplying liquid refrigerant from the condenser to said freezer and said refrigerating unit, said means including a liquid supply line leading from the condenser to line for the refrigerant compartment of the freezer, an expansion valve positioned in said line at a point near the freezer, and a liquid feed line for conducting refrigerant from the supply line for the freezer to the cooling element of said refrigerating unit, said feed line connecting with the supply line for the freezer at a point between the freezer and the expansion valve positioned in the freezer supply line, thereby providing a. path whereby upon closing of the vapor return for the freezer, liquid refrigerant, and any oil entrained therewith, remaining in the freezer may be removed from the latter and conducted through said cooling element to the suction compartment of the compressor, thereby preventing accumulation of oil in the refrigerant compartment of the freezer.

5. Apparatus of the character described, comprising, in combination, a freezer provided with a. compartment for receiving a refrigerating medium, a compressor, a condenser associated with said compressor, a refrigerating unit, including a cooling element provided with an expansive valve, a vapor return line for conducting vaporized refrigerant from the freezer to the condenser, a

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second vapor return line forconducting vaporized refrigerant from the refrigerating unit to the return line for the freezer, valve means interposed in the vapor return for the freezer at its point of connection with the return for said refrigerating unit for simultaneously opening one of said returns and closing the other, and means for supplying liquid refrigerant from the condenser to said compressor and said refrigerating unit, said means including a liquid supply line leading from the condenser to the refrigerant-compartment of the'freezer, an expansion valve positioned in said line-at a point near the freezer, and a liquid feed line for conducting refrigerant from the supply the freezer to the cooling element of said refrigerating unit, said feed line connecting with the supply line for the freezer at a point between the freezer and the expansion valve positioned in the freezer supply line, thereby providing a path whereby upon closing of the vapor return line for the freezer and opening of the vapor return line for said refrigerating unit, liquid refrigerant, and any oil entrained therewith, remaining in the-freezer may be removed from the latter and conducted through said cooling element to the suction compartment of the compressor, thereby preventing accumulation of oil in the refrigerant compartmentpf the freezer.

6. Apparatus of the character described comprising, in combination, a freezer, including a compartment for receiving a refrigerating medium, a compressor, a condenser associated with said compressor, connections for supplying liquid refrigerant from said condenser to the freezer and for returning vaporized refrigerant from the freezer to the compressor, means for interrupting the flow of vaporized refrigerant from the freezer, and means preventing accumulation of oil in the refrigerant compartment of the freezer, said means comprising a heat exchange element provided with an expansion valve, and the connections for removing liquid refrigerant from the freezer through said exchange element and expansion valve to the suction compartment of the compressor.

JAMES T. SMITH. 

